What metal is Rotax exhaust?

If it is a Rotax factory exhaust it is stainless.  The exact grade is shown in the installation manual.  Be aware that many OEM created their own systems and even may appear to be the same.  For example Kitfox made their own, many models of the Tecnam  and Bristel are made by Tecnam and others.  

Cheers

Any idea what material the Tecnam exhausts are made of?

This would be a question for your Tecnam dealer or the Tecnam factory.

Cheers

A couple of years back I worked on a study of exhaust failures for a particular SLSA manufacturer. If memory serves me correctly...

Rotax supplied cylinder port connector: 304 Stainless

Rotax supplied cylinder port connector flange: 316 Stainless

Most Third-Party Header Tubes: 304 Stainless

Most Third-Part Muffler assembly: 304 Stainless

There is some logic to this.  304 is slightly more machinable and formable, which is good for forming the header tubes and connectors.  And all the parts that are welded together are all 304, so you are not welding different grades together. The flanges, which are 316, are a stamped part so forming is not a problem.  Also, 316 offers a little more strength under high heat conditions so they will better resist deforming under the pressure of the exhaust fixing nuts when hot. 

Hi All

The Rotax muffler kit, used by some OEM, has all the material call-outs in the installation manual.  The socket at the head, the pipe between and the tailpipe supplied are indeed all 304.  The other parts vary due to application.  

Cheers